Electric heater.



PA'IENTED APR. 5, 1904 R. KUHN. ELECTRIC HEATER.

APPLIOATION FILED OUT. 'I, 1902.

H0 MODEL.

Tran 14 150 f" Patented April 5, 1904,

UNITED STATES PATENT OFFICE.

ROBERT KUHN, OF DETROIT, MICHIGAN, ASSIGNOR TO UNITED ELECTRK' HEATING CO., OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

ELECTRIC HEATER.

SPECIFICATION forming part of Letters Patent No. 756,242, dated April 5, 1904.

Application filed October 7, 1902.

To all whom it may concern:

Be it known that I, ROBERT KUHN, a citizen of the United States, residing at Detroit, in the county of Wayne and State of Michigan, have invented certain new and useful Improvements in Electric Heaters, of which the follow:

.ing is a specification,reference being had therein to the accompanying drawings.

The invention relates to electric heaters, and more particularly to a construction adapted for use'in cooking food, heating glue, &c.

It is the object of the invention to obtain a simple construction which is inexpensive to build and which is economical in the consump tion of current.

It is a further object to provide a construction especially adapted for use in place of the ordinary double boilers.

The invention therefore consists in the construction as hereinafter described and claimed.

In the drawings, Figure l is a vertical central section through the heater. Fig. 2 is a similar view through a modified construction, and Fig. 3 is an elevation View of the receptacle with the heating-coil wound thereon. Fig. 4 is a section on line 00 (r, Fig. 2.

It is one of the objects of the invention to apply the heat generated by the electric current as directly as possible. I have therefore devised a construction in which the heatingcoil is wound around the receptacle containing the material to be heated.

As shown in Fig. 1, A is a receptacle of cylindrical form. B is a wrapping of insulating material, which is preferably a thin sheet of mica. Around this wrapping is wound the heating-coil C, which may be of any suitable material, and in winding the convolutions are slightly spaced from each other, so as to compel the current to pass through the entire wire. The receptacle A is provided at its upper end with a laterally-extending flange D, which is supported uponan outer casing E. The flange D and the outer casing E are preferably secured to each other, so as to form a practically air-tight chamber F, in which the coil C is located and which forms a jacket for preventing loss of heat. The outer casing is provided with a handle G, preferably in the Serial No. 126,353. (No model.)

form of a tube, and the terminals of the coil 5 ably formed by a laterally-extending annular 6O flange a at the upper end of the portion A and an upwardly-extending cylindrical flange b. The whole constitutes a waterjacket which surrounds an inner receptacle I, supported by a flange or ring J, resting upon the flange I). 5

The inner receptacle I is of but slightly lesser diameter than the cylindrical portion A of the jacket. Th us when water is placed in the space between the receptacle and jacket it will form but a thin partition between the outercasing 7 having the heating-coil attached thereto and the inner receptacle. As a consequence whenever the heater is used it will take but a short time to beat this water partition and to com-.

municate the heat to the material within the inner receptacle. If the jacket A were of uniform diameter from top to bottom, only a small volume of water could be placed therein, and in use this would soon boil away,

thereby endangering the overheating of the material within the inner receptacle. To avoid this difliculty, I have provided the jacket with the enlargement H, which is adapted to receive a suflicient volume of water to maintain a practically constant level. that the coil surrounds only the lower part of the jacket and not the portion H. Thus the water will be heated onlyin the narrow space between the cylindrical portion A and the inner receptacle, while the water in the portion 9 H receives its heat only indirectly from the water lower down. As a consequence most of the heatimparted by the coil to the water in the lower part of the jacket will be absorbed by the material within the receptacle before it can be communicated to the water in the upper portion H. This will tend to pre ventthe loss of water through steaming away,

In this con-'55 It is to be noticed 5 as the Water in the upper portion will scarcely reach the boilingpoint. The jacket A is preferably inclosed in an outer casing J similar to the casing E of the other construction.

What I claim as my invention is 1. In an electric heater the combination with a receptacle for the material to be heated, of a heating-coil wrapped around the receptacle, and an outer closed casing surrounding but spaced from the coil.

2. In an electric heater,the combination with a cylindrical receptacle for the material to be heated, an insulated wrapping for saidreceptacle, a heating-coil of naked wire wound upon said wrapping and a surrounding airtight easing inclosing said coil.

3. In an electric heater,thecombination with a receptacle, a surrounding Water-jacket therefor having a body portion of but slightly greater diameter than said receptacle, an upper portion of greater diameter forming a storage-receptacle, and a heating-coil wound around said lower portion.

4. In an electric heater,the combination with a receptacle, a surrounding water-jacket having a lower heating portion of but slightly greater diameter than said receptacle and an upper portion of increased diameter, a heating-coil wound around said lower portion and a casing surrounding said lower coil and forming a support, upon which the upper part of said receptacle rests.

In testimony whereof I aflix my signature in presence of two witnesses.

ROBERT KUHN. Witnesses:

M. B. ODoGHnR'rY, H. C. SMITH. 

